1. Field of the Invention
The present invention relates to a heat sink with a plurality of heat dissipating fins and centrifugal fan, and in particular to a compact heat sink with centrifugal fan excellent in heat transfer efficiency which has a large amount of ventilation.
2. Description of the Related Art
Since the heat density of the devices and the heat generated by the CPU, devices or the like increases, it is desired that a heat sink excellent in heat dissipating efficiency with high performance is developed. Furthermore, since the height of the electronics devices such as a personal computer, game device or the like is limited, it is desired that a compact heat sink excellent in heat dissipating efficiency with low noise is developed. A heat sink made of aluminum extruded material with low manufacturing cost has been widely used. Since the heat sink made of aluminum extruded material is manufactured as one unit in which the heat receiving block and the heat dissipating fins are integrally formed, it is easy to manufacture. However, the heat sink made of aluminum extruded material has a technical problem in which the pitch between the fins is restricted to a certain degree due to the manufacturing technology, thus fins with fine pitch are difficult to be produced.
It is difficult to satisfy the increase of the amount of the generated heat by the combination of the heat receiving block and the heat dissipating fins, resulting in the heat sink with the use of the heat pipe. The heat sink with a heat receiving block and a plurality of heat pipes is widely used in which one end of the heat pipes are attached to the heat receiving block, and a plurality of heat dissipating fins are fixed on the heat pipes in such manner that the heat pipes are vertically arranged and inserted into the heat dissipating thin fins. Heat pipes used in the above manner make the heat dissipating area to be increased, and to improve fin efficiency, enabling to dissipate a large amount of the generated heat.
The space is provided within the interior of the heat pipe which becomes a flow channel for the working fluid. The working fluid received within the space functions to cause phase transition such as vaporization, condensation or the like and movement, thus the heat is transferred. More specifically, the working fluid is vaporized in the heat absorbing side by the heat generated by the heat generating component and transferred through the material forming the heat pipe, and then the vaporized working fluid moves toward the heat dissipating side of the heat pipe. The vaporized working fluid is cooled to return to a liquid phase thereof in the heat dissipating side. Thus liquid phase working fluid circulates back to the heat absorbing side of the heat pipe. The heat is transferred by the phase transition of the working fluid and the movement.
In general, in the heat sink with a heat receiving block and a plurality of heat pipes in which one end of the heat pipes are attached to the heat receiving block, and a plurality of heat dissipating fins are fixed on the heat pipes in such manner that the heat pipes are vertically arranged and inserted into the heat dissipating thin fins, a fan is installed to the vertical side of the layered heat dissipating fins to forcefully cool the heat dissipating fins to which the heat generated by the component to be cooled is transferred through the heat pipes (refer to Japanese patent application publication No. Hei 11-351769; Japanese patent application publication No. 2001-210767).
However, the vertical side of the conventional heat sink with the cooling fan as described above has the same height as the vertically installed cooling fan, thus the height of the fan becomes high. When the above-mentioned heat sink is applied to the electronics device such as the personal computer, game device or the like, the height of which is restricted, the height of the heat dissipating fin has to be changed lower. More specifically, the heat sink having a size horizontally long is used to have a horizontally wide heat dissipating fin. In order to cool the heat sink with the thin fins of the size horizontally wide, many fans with small diameter has to be installed, thus the number of the fans becomes large to result in the large noise. Furthermore, the size of the air discharge port becomes large, leading to the large size of the box with various terminals appropriately arranged.
In addition, since many heat generating devices are installed within the box to effect the higher performance, it is necessary to more effectively lower the temperature within the box.